Merge pull request #793 from flip111/patch-2

Improved error messages in Paginator: LimitSubqueryOutputWalker

lib/Doctrine/ORM/Tools/Pagination/LimitSubqueryOutputWalker.php

@@ -149,6 +149,10 @@ class LimitSubqueryOutputWalker extends SqlWalker
             }
         }
 
+        if (count($sqlIdentifier) === 0) {
+            throw new \RuntimeException('The Paginator does not support Queries which only yield ScalarResults.');
+        }
+
         if (count($rootIdentifier) != count($sqlIdentifier)) {
             throw new \RuntimeException(sprintf(
                 'Not all identifier properties can be found in the ResultSetMapping: %s',